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Default Sony 36" TV with impure lower-right corner

Because another poster has problems with bad corner purity in a Sony TV,
this might be a good time to bring up my related problem.

I have a 36" 400-series flat-CRT WEGA. I had no problems with it until a day
when a discussion on rec.antiques.radio+phono prompted me to magnetize the
aperture grille by turning off a bulk tape eraser near it -- very near it.
(The point was to show that you couldn't magnetize the grille so much that
it couldn't be demagnetized. Yeah.)

You know the rest. I now have a permanent mostly-blue splotch at the
lower-right corner. The integral degausser has no effect, and the same bulk
eraser that created the problem will not reverse it. It's a pretty nasty
impurity (though, fortunately, rarely visible on 4:3 material, and outside
the range when 16:9 material is displayed).

I initially thought the bulk eraser had demagnetized one or more of the trim
magnets on the CRT. But that doesn't make much sense, because there's no way
a good sample of any CRT would show that much impurity before trim magnets
were applied. Likewise, I doubt that something got irreversibly magnetized.

Someone suggested that the aperture grille was damaged at the initial
demagnetizer shut-off. Any opinions about this, and if so, how the problem
might be reversed?

Thanks in advance.


As a side remark (which is for interest, not discussion), I also have a 32"
Toshiba IDTV. When purchased, it had an impurity splotch at the lower-right
corner that would not go away. I assumed it was shipping damage (this
particular model was notorious for suffering shipping damage), and lo and
behold, when I moved from my apartment to a condo, the jostling corrected
the problem. No more impurity.





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Default Sony 36" TV with impure lower-right corner

"Meat Plow" wrote in message
...

Borrow a degausser and give it a try.


No offense, but why should a degausser work, when a bulk tape eraser with
the power to handle metal-particle tape doesn't? You have to stand about 8'
from the set before the bulk eraser's effect is no longer visible.


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Default Sony 36" TV with impure lower-right corner

On Feb 8, 12:33*pm, "William Sommerwerck"
wrote:
"Meat Plow" wrote in message

...

Borrow a degausser and give it a try.


No offense, but why should a degausser work, when a bulk tape eraser with
the power to handle metal-particle tape doesn't? You have to stand about 8'
from the set before the bulk eraser's effect is no longer visible.


William:

The inductive kick when the eraser was shut off is quite large. If
you bring the bulk eraser to the same location as before, can you see
any effect on the picture? If you can, try turning it on and move it
slowly away to several feet before shutting off.

I would take a very strong magnet, such as from an old magnetron,
bring it near to the tv, in the same place as the eraser was when you
shut it off, and then rotate the magnet rapidly wile slowly moving it
away from the tv. It effectively reverses the magnetism back and
forth while slowly reducing the strength. That will clear many
problems in my experience. I have a dozen old magnets from scrapped
uwave ovens, they are about the strongest I can find except for
magnets from very large loudspeakers and are so strong you don't want
your finger between two of them.

H. R. (Bob) Hofmann
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Default Sony 36" TV with impure lower-right corner

No offense, but why should a degausser work, when a bulk tape eraser
with the power to handle metal-particle tape doesn't? You have to stand
about 8' from the set before the bulk eraser's effect is no longer
visible.



The inductive kick when the eraser was shut off is quite large.
If you bring the bulk eraser to the same location as before, can you
see any effect on the picture? If you can, try turning it on and move
it slowly away to several feet before shutting off.


Are you kidding? grin The bulk eraser has a huge effect.

My approach has been to follow the standard procedure -- bring the
demagnetizer near the set, then slowly back away to let the flux gradually
decline, until there is no visible effect on the image. This does _not_
remove the splotch.


I would take a very strong magnet, such as from an old magnetron,
bring it near to the TV, in the same place as the eraser was when you
shut it off, and then rotate the magnet rapidly while slowly moving it
away from the TV. It effectively reverses the magnetism back and
forth while slowly reducing the strength. That will clear many problems
in my experience. I have a dozen old magnets from scrapped uwave
ovens, they are about the strongest I can find except for magnets
from very large loudspeakers and are so strong you don't want
your finger between two of them.


How is this approach different from slowly moving a degaussing away from the
CRT? Is the magnetron magnet significantly stronger than a degaussing coil?
(The implication of what you wrote is that it is.)

Zenith used to make a bar magnet on the end of stick. You started the magnet
spinning (by hand), then pulled it away from the CRT. The idea was to clear
small splotches of magnetism.

Somebody suggested that I had damaged the aperture grille. Is this possible?
Does anyone know?

Back in 2006, a friend helped me disassemble one of my Apogee speakers
(which has lots of magnets). The speaker came rather close to the set, and
for a few minutes the splotch was gone. (And, no, the speaker is not the
cause of the splotch.)


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Default Sony 36" TV with impure lower-right corner

On Feb 8, 4:16*pm, "William Sommerwerck"
wrote:
No offense, but why should a degausser work, when a bulk tape eraser
with the power to handle metal-particle tape doesn't? You have to stand
about 8' from the set before the bulk eraser's effect is no longer
visible.

The inductive kick when the eraser was shut off is quite large.
If you bring the bulk eraser to the same location as before, can you
see any effect on the picture? If you can, try turning it on and move
it slowly away to several feet before shutting off.


Are you kidding? grin The bulk eraser has a huge effect.

My approach has been to follow the standard procedure -- bring the
demagnetizer near the set, then slowly back away to let the flux gradually
decline, until there is no visible effect on the image. This does _not_
remove the splotch.

I would take a very strong magnet, such as from an old magnetron,
bring it near to the TV, in the same place as the eraser was when you
shut it off, and then rotate the magnet rapidly while slowly moving it
away from the TV. It effectively reverses the magnetism back and
forth while slowly reducing the strength. That will clear many problems
in my experience. I have a dozen old magnets from scrapped uwave
ovens, they are about the strongest I can find except for magnets
from very large loudspeakers and are so strong you don't want
your finger between two of them.


How is this approach different from slowly moving a degaussing away from the
CRT? Is the magnetron magnet significantly stronger than a degaussing coil?
(The implication of what you wrote is that it is.)

Zenith used to make a bar magnet on the end of stick. You started the magnet
spinning (by hand), then pulled it away from the CRT. The idea was to clear
small splotches of magnetism.

Somebody suggested that I had damaged the aperture grille. Is this possible?
Does anyone know?

Back in 2006, a friend helped me disassemble one of my Apogee speakers
(which has lots of magnets). The speaker came rather close to the set, and
for a few minutes the splotch was gone. (And, no, the speaker is not the
cause of the splotch.)


OK - what I would try next is turning the bulk eraser on and off in
the same position that it was when you caused the problem, to see what
happens. If it was the bulk eraser that casued the problem, something
should change. If nothing changes, then maybe there is something else
magnetized somewhere else in the set. Is it possible something got
magnetized and then moved so that it is no longer affected by the bulk
eraser? Have you pulled the back to see if anything seems out of
place?

Bob Hofmann


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Default Sony 36" TV with impure lower-right corner

William Sommerwerck wrote:
snip
Back in 2006, a friend helped me disassemble one of my Apogee speakers
(which has lots of magnets). The speaker came rather close to the set, and
for a few minutes the splotch was gone. (And, no, the speaker is not the
cause of the splotch.)


I'm guessing--and it's only a guess--that you did, indeed, damage the
aperture screen...deformed would be more accurate. The fact that a
permanent magnet in proximity to the crt temporarily 'fixed' it is both
a clue and a path to a fix of sorts.

I'm thinking that the field from the magnet pulled the grill back into
shape--and that the effect should be repeatable. Although it's not
really a cure, leaving a magnet in proximity to your TV is preferable to
watching a splotch....

jak
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Default Sony 36" TV with impure lower-right corner

On Feb 8, 11:03*pm, jakdedert wrote:
hr(bob) wrote:
On Feb 8, 4:16 pm, "William Sommerwerck"



snip

OK - what I would try next is turning the bulk eraser on and off

in
the same position that it was when you caused the problem, to see

what
happens. *If it was the bulk eraser that casued the problem,

something
should change. *If nothing changes, then maybe there is something

else
magnetized somewhere else in the set. Is it possible something

got
magnetized and then moved so that it is no longer affected by the

bulk
eraser? *Have you pulled the back to see if anything seems out of
place?


Bob Hofmann


What you're suggesting is to repeat the same thing which he (and I)
suspect damaged the tube in the first place--abruptly and possibly
permanently flexing the shadow mask. *The possibility exists that

he
could make it even worse. *Unless concentrated degaussing of the

area
makes some improvement, internal damage is about the only

possibility.

jak


Trinitron aperture grills are stretched top to bottom on a cast iron
frame inside the CRT. How do you 'deform' it?

GG
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Default Sony 36" TV with impure lower-right corner

wrote in message
...

Trinitron aperture grills are stretched top to bottom on a cast iron
frame inside the CRT. How do you 'deform' it?

Twisting it?


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"jakdedert" wrote in message
.. .

I'm guessing--and it's only a guess--that you did, indeed, damage
the aperture grille... Deformed would be more accurate. The fact
that a permanent magnet in proximity to the CRT temporarily
"fixed" it is both a clue and a path to a fix of sorts.


I'm thinking that the field from the magnet pulled the grill back into
shape--and that the effect should be repeatable. Although it's not
really a cure, leaving a magnet in proximity to your TV is preferable
to watching a splotch...


Agreed. I've put up with it for a few years, so there's no need to fix it
immediately. I'll start looking for a magnetron magnet.

And I might just call Sony and ask their opinion. (Hah!) In fact, as the set
came from Magnolia, I just might stop by (when I get a car!) and ask.


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William Sommerwerck wrote:
"jakdedert" wrote in message
news
hr(bob) wrote:


OK - what I would try next is turning the bulk eraser on and off in the
same position that it was when you caused the problem, to see what
happens. If it was the bulk eraser that casued the problem, something
should change. If nothing changes, then maybe there is something else
magnetized somewhere else in the set. Is it possible something got
magnetized and then moved so that it is no longer affected by the bulk
eraser? Have you pulled the back to see if anything seems out of
place?


What you're suggesting is to repeat the same thing which he (and I)
suspect damaged the tube in the first place--abruptly and possibly
permanently flexing the shadow mask. The possibility exists that he
could make it even worse. Unless concentrated degaussing of the area
makes some improvement, internal damage is about the only possibility.


I hadn't thought of that. The bulk eraser runs about a minute before it cuts
out, possibly longer if I leave it in the freezer overnight. Perhaps a hair
of the dog that bit the set might work...


I'm not a TV tech...don't even play one on the internet; but I do know
that bulk erasers put out a pretty hefty field. I'd go for something
with a little less flux that you could keep on longer...and keep it
moving. The Weller soldering gun somebody mentioned is what I've used
for 'spot' degaussing.

jak
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Default Sony 36" TV with impure lower-right corner

On Feb 9, 11:25*am, jakdedert wrote:
William Sommerwerck wrote:
"jakdedert" wrote in message
news
hr(bob) wrote:


OK - what I would try next is turning the bulk eraser on and off in the
same position that it was when you caused the problem, to see what
happens. *If it was the bulk eraser that casued the problem, something
should change. *If nothing changes, then maybe there is something else
magnetized somewhere else in the set. Is it possible something got
magnetized and then moved so that it is no longer affected by the bulk
eraser? Have you pulled the back to see if anything seems out of
place?


What you're suggesting is to repeat the same thing which he (and I)
suspect damaged the tube in the first place--abruptly and possibly
permanently flexing the shadow mask. The possibility exists that he
could make it even worse. Unless concentrated degaussing of the area
makes some improvement, internal damage is about the only possibility.


I hadn't thought of that. The bulk eraser runs about a minute before it cuts
out, possibly longer if I leave it in the freezer overnight. Perhaps a hair
of the dog that bit the set might work...


I'm not a TV tech...don't even play one on the internet; but I do know
that bulk erasers put out a pretty hefty field. *I'd go for something
with a little less flux that you could keep on longer...and keep it
moving. *The Weller soldering gun somebody mentioned is what I've used
for 'spot' degaussing.

jak- Hide quoted text -

- Show quoted text -


If the bulk eraser will stay on for even 20 secondds, that is enough
to turn it on, move it around the area of the tv where it was before,
and then back away slowly.

H. R. Hofmann
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Default Sony 36" TV with impure lower-right corner


"William Sommerwerck" wrote in message
. ..
"jakdedert" wrote in message
.. .

I'm guessing--and it's only a guess--that you did, indeed, damage
the aperture grille... Deformed would be more accurate. The fact
that a permanent magnet in proximity to the CRT temporarily
"fixed" it is both a clue and a path to a fix of sorts.


I'm thinking that the field from the magnet pulled the grill back into
shape--and that the effect should be repeatable. Although it's not
really a cure, leaving a magnet in proximity to your TV is preferable
to watching a splotch...


Agreed. I've put up with it for a few years, so there's no need to fix it
immediately. I'll start looking for a magnetron magnet.

And I might just call Sony and ask their opinion. (Hah!) In fact, as the
set
came from Magnolia, I just might stop by (when I get a car!) and ask.



Another source of magnets that are very strong and easy to obtain is the
motor drive from the old 5 1/4 floppy drives from computers. They are
usually discarded everywhere.
Justy.


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On Feb 9, 1:19*pm, "William Sommerwerck"
wrote:
"hr(bob) " wrote in message

...

If the bulk eraser will stay on for even 20 secondds, that is
enough to turn it on, move it around the area of the TV,
where it was before and then back away slowly.


I've done that many times, and it doesn't fix the problem.


Does that blulk eraser cause the colors in the corner to swirl around?

Maybe just glue some magnetic rubber to the inside of the cabinet near
the corner in question if you can fix the color in the corner that
way.

I'm out of any other ideas.
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On Feb 11, 6:58*am, "William Sommerwerck"
wrote:
"hr(bob) " wrote in message

...

Does that blulk eraser cause the colors in the corner
to swirl around?


Of course! It's rat purty.

Maybe just glue some magnetic rubber to the inside
of the cabinet near the corner in question if you can fix
the color in the corner that way.


I might experiment with magnetic business cards.

I'm out of any other ideas.


Damn. I was expecting omniscience.


I'm damn good, but not God. G
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